How to eliminate problems with incorrect interpretation of the IFC model
| Product | InstalSystem 5 |
| Type of article | TIP&TRICK |
| Source for translation | 2026-04-03 |
Problem description
After performing the operations Creates walls from an IFC file, Creates slabs from an IFC file, Creates roofs from an IFC file or Creates windows, doors, and wall openings from an IFC file (For more information, see: BIM - Interpretation of IFC elements into building structure elements of InstalSystem 5 package) some IFC elements may be incorrectly recognized by the program due to inaccuracies in the imported IFC model. This affects the precise generation of the Thermal model. Such misinterpretations are not always indicated by diagnostic messages. Therefore, it is highly recommended to check the created Building structure in 2D editor and on 3D view after making the interpretation.
This article describes the most frequently occurring difficulties and the ways to eliminate them:
Attention! When the imported IFC model contains incomplete or inconsistent walls / slabs / roofs, choose the IfcSpace + Building contour interpretation. This native InstalSystem workflow reconstructs walls, slabs and roofs from bounded spaces and the Building contour, making the result more robust to element-level errors and better suited for complex building geometries:
- Use the function Create storeys between selected slabs/roofs from IFC file. For more information, see: Storeys between indicated slabs/roofs from IFC file;
- Perform the interpretation of ifcSpace elements followed by the creation of a Building contour and use of the Automatic walls, slabs and roofs function. For more information, see: Using the rooms from ifcSpace in the Automatic walls, slabs and roofs operation;
- Use Creates windows, doors, and wall openings from an IFC file function.
Prerequisites and limits: Requires properly closed IfcSpace boundaries and valid Storey elevations. If spaces are missing or open, results may be incomplete - verify generated geometry afterwards.
Note: If direct element interpretation fails or produces gaps - switch to IfcSpace + Building contour method. If both methods are available and consistent, choose the direct element interpretation.
Solution
The Automatic Room is not created
The video below shows an example where the Automatic Room is not created.
Reason: The structural Wall element, interpreted from ifcWall element, overlaps the other. This is indicated by a diagnostic message Wall edges are close to each other but not connected.
Solution: Correct the structural elements and make the Computation of building structure .
One Automatic Room created instead of several on the last storey
The video below shows an example where one Automatic Room is created instead of several.
Reason: The internal Wall elements interpreted from ifcWall objects are not in contact with the Roof.
Solution: Adjust the height of the walls, perform the Computation of building structure .
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